This application relates generally to establishing radio access bearers in a mobile telecommunications network and, more particularly, to selectively establishing radio access bearers to support simultaneous voice and data communications in a mobile telecommunications network.
Some mobile telecommunications networks, such as those based upon Universal Mobile Telecommunications System (“UMTS”), utilize a bearer service called a radio access bearer (“RAB”) to establish voice and/or data connections between a mobile device and a core network. UMTS permits the simultaneous transmission of voice and data content over a special-purpose RAB called a multi-RAB (also called an “mRAB”). When a subscriber is using their mobile device for voice communications and the network has data to transmit to the mobile device, the network and the mobile device jointly establish an mRAB to support simultaneous transmission of voice and data content. Similarly, an mRAB can be established if the subscriber takes actions to initiate a data transfer, such as by initiating a download or launching an application that relies on a data connection to populate its content.
Communications over an mRAB are not without complications. For example, a mobile device using an mRAB for voice and data communications is required to supply sufficient uplink transmit power to support both the voice and data components of the mRAB. Under some conditions, such as when the mobile device is approaching the edge of network coverage, the mobile device may use all or at least a majority of its available uplink transmit power to maintain acceptable voice quality for a voice call. When an mRAB is invoked to transfer data, the radio link budget is impaired by several decibels, at which point the mobile device can no longer support both the voice and data components. If either component fails, the mRAB is torn down, resulting in a dropped call. The subscriber is likely unaware of the underlying mechanisms that forced their call to be dropped, particularly for scenarios in which a background service, such as an email push, forced establishment of the mRAB while the subscriber was on the call.
Recent performance trends in UMTS-based networks have shown that the number of dropped voice calls due to mRAB connections can be several times the number of dropped voice calls when a voice-only RAB is used. Mobile network operators may want to promote their competitive advantage in offering wireless service that allows simultaneous voice and data. In doing so, however, these mobile network operators may also exacerbate the aforementioned problems leading to a higher frequency of dropped calls and, as a result, reduced consumer confidence, bad press, decreased subscriber retention, and revenue loss.